The present invention relates to a thermal sensitivity calculating apparatus for calculating thermal sensitivity, e.g., an equivalent temperature (Teq), felt by a human body.
An equivalent temperature Teq is used as an evaluation index of a thermal environment felt by a human body, i.e., thermal sensitivity.
As the first method of obtaining this equivalent temperature Teq, a method has been proposed, in which an equivalent temperature Teq.sup.* substantially equal to the equivalent temperature Teq is obtained by measuring a radiant temperature Tr, an air temperature Ta, and an air velocity Vair by using different sensors, and performing predetermined arithmetic processing of the measured values. This method requires complicated arithmetic processing, and the processing time is undesirably prolonged.
Under the circumstances, as the second method of obtaining the equivalent temperature Teq, a method is proposed, in which a heater is incorporated in a module main body, and the amount of power to be supplied to the heater is controlled to always keep a temperature (sensor temperature) T.sub.cr of the module main body to be a constant value (e.g., 36.5.degree. C.). According to this method, the equivalent temperature Teq.sup.* can be calculated by measuring the amount of power to be supplied to the heater and performing predetermined arithmetic processing of the measured value.
In the second method described above, however, since an environment measuring section constituted by the module main body and the heater is much smaller than a human body, as is apparent, the air current sensitivity of the measuring section is much larger than that of the human body.
This difference in air current sensitivity indicates that the equivalent temperatures Teq and Teq.sup.* remain substantially equal to each other at an air velocity of less than 0.1 m/s but differ from each other when the air velocity is increased to 0.1 m/s or more. More specifically, at an air velocity of 0.1 m/s or more, the equivalent temperature Teq.sup.* becomes lower than the equivalent temperature Teq. As a result, accurate measurement cannot be performed.
According to the second method described above, however, there is a critical drawback that accurate measurement cannot be performed when the air velocity Vair is high, in spite of the advantage that the radiant temperature Tr, the air temperature Ta, and the air velocity Vair can be integrally measured, i.e., the advantage that the arithmetic processing can be simplified.